| First Author | Ang RL | Year | 2021 |
| Journal | Proc Natl Acad Sci U S A | Volume | 118 |
| Issue | 50 | PubMed ID | 34887354 |
| Mgi Jnum | J:335160 | Mgi Id | MGI:7466470 |
| Doi | 10.1073/pnas.2001602118 | Citation | Ang RL, et al. (2021) Immune dysregulation in SHARPIN-deficient mice is dependent on CYLD-mediated cell death. Proc Natl Acad Sci U S A 118(50) |
| abstractText | SHARPIN, together with RNF31/HOIP and RBCK1/HOIL1, form the linear ubiquitin chain assembly complex (LUBAC) E3 ligase that catalyzes M1-linked polyubiquitination. Mutations in RNF31/HOIP and RBCK/HOIL1 in humans and Sharpin in mice lead to autoinflammation and immunodeficiency, but the mechanism underlying the immune dysregulation remains unclear. We now show that the phenotype of the Sharpin(cpdm/cpdm) mice is dependent on CYLD, a deubiquitinase previously shown to mediate removal of K63-linked polyubiquitin chains. Dermatitis, disrupted splenic architecture, and loss of Peyer's patches in the Sharpin(cpdm/cpdm) mice were fully reversed in Sharpin(cpdm/cpdm) Cyld(-/-) mice. We observed enhanced association of RIPK1 with the death-signaling Complex II following TNF stimulation in Sharpin(cpdm/cpdm) cells, a finding dependent on CYLD since we observed reversal in Sharpin(cpdm/cpdm) Cyld(-/-) cells. Enhanced RIPK1 recruitment to Complex II in Sharpin(cpdm/cpdm) cells correlated with impaired phosphorylation of CYLD at serine 418, a modification reported to inhibit its enzymatic activity. The dermatitis in the Sharpin(cpdm/cpdm) mice was also ameliorated by the conditional deletion of Cyld using LysM-cre or Cx3cr1-cre indicating that CYLD-dependent death of myeloid cells is inflammatory. Our studies reveal that under physiological conditions, TNF- and RIPK1-dependent cell death is suppressed by the linear ubiquitin-dependent inhibition of CYLD. The Sharpin(cpdm/cpdm) phenotype illustrates the pathological consequences when CYLD inhibition fails. |
